Method and apparatus for managing power of portable computer system

ABSTRACT

Provided is a method and apparatus for managing the power of a portable computer system, in which a convenient user interface is provided. The method includes calculating a range of a desired time-of-use based on power consumption of the portable computer system and a remaining battery capacity at a minimum power level of the portable computer system, providing the calculated range of the desired time-of-use and a desired time input box that allows a user to input the desired time-of-use, inputting the desired time-of-use through the desired time input box, and resetting the power level of the portable computer system according to the input desired time-of-use.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit under 35 U.S.C. §119(a) of KoreanPatent Application No. 10-2004-0055249 filed on Jul. 15, 2004 in theKorean Intellectual Property Office, the entire disclosure of which ishereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the power management for a portablecomputer system. More particularly, the present invention relates to amethod and apparatus for managing the power of a portable computersystem, in which a convenient user interface is provided.

2. Description of the Related Art

Users often need to use portable computers in mobile environments. Inmobile environments, users do not have access to a typical alternatingcurrent (AC) power source for their computers. In this situation, arechargeable battery is generally used as a power supply instead of anAC power source. The amount of energy stored in a battery isproportional to the weight of the battery. In other words, to store moreenergy in a battery, the battery's weight inevitably must increase.Thus, a great amount of research has been conducted to improve theenergy density and stability of batteries. As a result of such research,nickel cadmium (NiCd) batteries, nickel metal hydride (NiMH) batteries,lithium (Li+) batteries, and lithium polymer batteries have beenproduced in great numbers. Also, a fuel cell technology is being studiedfor use in mobile environments as a computer power supply. Although theamount of computing time users are getting in mobile environments can beincreased by using a superior battery or many batteries, a battery witha high energy density is expensive and the use of many batteries resultsin an increase in the weight of a portable computer system. Inparticular, an increase in the weight of a portable computer system isan obstacle to the main advantage of the portable computer system, itsmobility.

Thus, methods for reducing unnecessary power consumption through thepower management of a portable computer system are being studied or havebeen developed. Korean Patent Publication No. 2002-0080615 discloses amethod for managing the battery power in a portable computer, in whichthe length of time a specific function designated by a user can be usedwith the remaining battery capacity is estimated and displayed throughmulti-level modes. Additionally, the length of time a specific functioncan be used is selected or variably controlled by selecting one of themulti-level modes, thereby effectively reducing unnecessary batterypower consumption of components that are unimportant when using thespecific function and increasing the length of time the specificfunction can be used.

In Japanese Patent Publication No. 1999-143595, the power capacity of adevice capable of setting a power saving mode and the power capacity ofa device incapable of setting a power consumption mode are measured. Theamount of power consumption by each device is recorded on a recordingmedium based on results of the measurement, and the recorded values areoccasionally updated. Thereafter the power consumption of each deviceand the power consumption of the device without setting the power savingmode are measured based on the remaining battery power and a powersaving setting level obtained from a recording medium. The operationtime according to remaining battery power is estimated based on thepower consumption of each device and the power consumption of the devicewithout setting the power saving mode and is output.

Such techniques can increase the length of time a portable computersystem can use a battery to a degree by preventing the unnecessary useof the battery. However, in most cases, users desire to secure the timerequired for a specific intended operation through a computer system,for example, one hour of word processing, instead of simply increasingthe length of time, for instance, an extra hour and fifteen minutes, thecomputer system can be used through complicated battery powermanagement. In other words, when users can sufficiently perform adesired operation with the remaining battery capacity, they may not feelthe need to manage the power of the portable computer system. Even whenpower management is required, users may desire to secure the time theycan work on computers by simply setting a desired amount of time, forinstance, one hour, instead of through complicated selection.

In Korean Patent Publication No. 2001-0096576, upon a user's input ofthe amount of time required for operating a data processing system, theamount of available power is identified, the amount of power consumed bythe data processing system when operating for the input amount of timeusing the available power is identified, and the amount of powerconsumption of the data processing system is set to the identifiedamount of power consumption. Thus, users can use the data processingsystem for a desired amount of time. However, Korean Patent PublicationNo. 2001-0096576 does not provide a limit on the amount of time input byusers, for example, information indicating that the maximum amount oftime input by users is 2 hours. As a result, if users input 3 hours asthe amount of time required for operating the data processing system,they only receive a warning message without achieving their goals.

Therefore, it would be beneficial to provide a method and apparatus formanaging the power of a portable computer, in which a limit on theamount of time users can use the portable computer and a convenient userinterface, are provided.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for managing thepower of a portable computer system, in which a convenient userinterface is provided.

The above stated object as well as other objects, features andadvantages, of the present invention will become clear to those skilledin the art upon review of the following description.

According to an aspect of the present invention, there is provided amethod for managing the power of a portable computer system. The methodcomprises calculating the range of a desired time-of-use based on powerconsumption and a remaining battery capacity at a minimum power level ofthe portable computer system, providing the calculated range of thedesired time-of-use and a desired time input box that allows a user toinput the desired time-of-use, inputting the desired time-of-use throughthe desired time input box, and resetting the power level of theportable computer system according to the input desired time-of-use.

According to another aspect of the present invention, there is providedan apparatus for managing the power of a portable computer system,comprising a graphical user interface which provides a user with therange of a desired time-of-use that is calculated based on the powerconsumption of the portable computer system at a minimum power level anda remaining battery capacity and includes a desired time input box thatallows the user to input the desired time-of-use as selected made by theuser, and a power manager which resets the power level of the portablecomputer system such that a total user time including the desiredtime-of-use input through the graphical user interface exceeds aremaining battery time.

According to still another aspect of the present invention, there isprovided a portable computer system comprising a battery unit whichsupplies power, a plurality of devices which provide predeterminedfunctions, a graphical user interface which provides a user with a rangeof a desired time-of-use that is calculated based on the powerconsumption of the portable computer system at a minimum power level anda remaining battery capacity and includes a desired time input box thatallows the user to input the desired time-of-use as selected by theuser, and a power manager which resets the power level of the portablecomputer system such that a total user time including the desiredtime-of-use input through the graphical user interface exceeds aremaining battery time for the present state of the portable computersystem.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 illustrates a user interface for power management according to anembodiment of the present invention;

FIG. 2 illustrates a user interface according to another embodiment ofthe present invention;

FIG. 3 is a flowchart illustrating a process for managing the power of aportable computer system according to an embodiment of the presentinvention;

FIG. 4 is a flowchart illustrating in detail a process for resetting apower level according to an embodiment of the present invention;

FIG. 5 is a flowchart illustrating in detail a process for resetting apower mode of a device according to an embodiment of the presentinvention;

FIG. 6 is a flowchart illustrating a process for managing the power of aportable computer system according to another embodiment of the presentinvention; and

FIG. 7 is a block diagram of an apparatus for managing the power of aportable computer system according to an embodiment of the presentinvention.

Like reference numerals refer to like elements throughout thespecification.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Advantages and features of the embodiments of the present invention andmethods of accomplishing the same may be understood more readily byreference to the following detailed description of exemplary embodimentsand the accompanying drawings. The present invention may, however, beembodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein. Rather, these embodimentsare provided so that this disclosure will be thorough and complete andwill fully convey the concept of the invention to those skilled in theart, and the present invention will only be defined by the appendedclaims.

The portable computer system used in the present invention operates witha battery power supply, preferably includes a plurality of devices withvarious functions such as a central processing unit (CPU), a displaydevice, and a storage device, and has a computing function. Since theportable computer system includes a battery, it can be used by a mobileuser. The portable computer system may use a typical alternating current(AC) power supply when available instead of the battery when the user isnot on the move. A representative example of the portable computersystem is a noteboOK computer, and the portable computer system may alsobe comprised in a personal digital assistant (PDA) or a mobile phonehaving a computing function.

Exemplary embodiments of the present invention will now be described inmore detail with reference to the accompanying drawings.

FIG. 1 illustrates a user interface for power management according to anembodiment of the present invention and FIG. 2 illustrates a userinterface according to another embodiment of the present invention. If auser inputs a desired amount of time (hereinafter referred to as a“desired time-of-use”) into a user interface for power management, anapparatus for managing the power of a portable computer system attemptsto secure the desired time-of-use with a remaining battery capacity byadjusting the power level of the portable computer system. The term“desired time-of-use” used in the embodiments of the present inventionmay be construed as including the amount of time the user desires to addto a current remaining battery time and. The amount of time the useractually desires to use the battery is the sum of the current remainingbattery time and the amount of time the user desires to add to thecurrent remaining battery time, hereinafter referred to as a “total usertime”. In the following embodiments, the desired time-of-use is definedas the amount of time the user desires to add to the current remainingbattery time. However, such a definition is only an example and thetechnical spirit of the present invention also includes a definitionwhere the desired time-of-use is the amount of time the user actuallydesires to use the battery or “total user time”.

Referring to FIG. 1, the user interface is preferably provided to a userin the form of a graphic user interface (GUI). The user interfaceincludes a before-input battery information box 110 that shows a powerstate before the user inputs an additional time, a time input box 120 towhich the user can input an additional time, a maximum additional timeinformation box 130, and an after-input battery information box 140.

The before-input battery information box 110 is provided to the user ina deactivated state and may include information such as a currentremaining battery capacity and the amount of time the battery can beused with the current remaining battery capacity.

A limit on the additional time that can be input by the user is providedthrough the maximum additional time information box 130. The maximumadditional time information box 130 is provided in a deactivated stateand shows the user the maximum time that can be added.

The user can recognize the range of the desired time-of-use through thebefore-input battery information box 110 and the maximum additional timeinformation box 130.

The time input box 120 is preferably provided to the user in anactivated state and the user can input the amount of time to beadditionally secured through the time input box 120. In an embodiment ofthe present invention, the time input box 120 includes a text box 121into which the user can input the amount of time to be additionallyobtained from managing the battery power. In another embodiment of thepresent invention, the time input box 120 includes a slider bar 123 thatallows the user to select an additional time between a minimumadditional time 124 and a maximum additional time 125. The user canselect a desired additional time by preferably clicking and dragging aslider 122 on the slider bar 123. In still another embodiment of thepresent invention, the time input box 120 includes the text box 121 andthe slider bar 123, and the slider 122 automatically moves to acorresponding additional time position on the slider bar 123 once theuser inputs a desired additional time into the text box 121. Also, oncethe user moves the slider 122 to a specific additional time position onthe slider bar 123, a corresponding additional time is automaticallywritten in the text box 121.

The time input box 120 may further include at least one check box fordesignating priority in reducing the power levels of devices. Forexample, when a user watches a movie, the brightness of a liquid crystaldisplay (LCD) may be important. In this case, the user can select an LCDcheck box 126 by clicking on the LCD check box 126 with an input device.Once the LCD check box 126 is selected, the power levels of devicesother than the LCD are reduced before the power level of the LCD tosecure an additional time desired by a user, for instance, 30 minutes.Similarly, when a specific program is installed in a hard disk (HDD),the user checks a HDD check box 127 with an input device. When the userwatches a movie from a compact disc read only memory (CD-ROM) drive or adigital versatile disc read only memory (DVD-ROM) drive, a reduction inthe power level of an optical device drive (ODD) such as the CD-ROM orthe DVD-ROM should be avoided, if possible. To this end, the user mayavoid such a reduction in the power level of the ODD by clicking on anODD check box 128 with the mouse. In this embodiment, once a device ischecked through a corresponding check box, adjustment of the power levelof the device is avoided. In an embodiment, if a device check box ischecked, the power level of a corresponding device is maintained higherthan a predetermined value. For example, when the LCD check box 126 isnot checked, the LCD may be powered off to reduce the power level of theLCD. However, if the LCD check box 126 is checked, the power level ofthe LCD is maintained higher than 50%. When a user listens to music, ahigher amount of power supplied to the LCD may be unnecessary. However,when a user watches a movie, it is essential that a greater amount ofpower be supplied to the LCD. Such a predetermined value may be presetto a proper value by a manufacturer of portable computers, but may bepreset by user's setting. If the LCD check box 126 is checked, themaximum additional time is automatically calculated again. In otherwords, the maximum power level that is calculated in a state where thepower level of the LCD is 0% should be calculated again in a state wherethe power level of the LCD is 50%.

The after-input battery information box 140 provides the user withinformation about the remaining battery capacity after the user inputsthe additional time and the remaining battery time.

The user interface may include an OK button 150, a cancel button 151,and an apply button 152. Once a user inputs an additional time or checksa check box and clicks the apply button 152 with the input device, theinformation set or changed by the user is stored. If the user clicks thecancel button 151 with the mouse, information set or changed by the useris not stored. If the user clicks the OK button 150 with the inputdevice, the information set or changed by the user is stored and theuser interface is terminated.

Next, referring to FIG. 2, the user interface according to anotherembodiment of the present invention includes a before-input batteryinformation box 210 that shows a power state before the user inputs anadditional time, a time input box 220 to which the user can input theadditional time, a maximum additional time information box 230, and anafter-input battery information box 240. The functions of thebefore-input battery information box 210 and the maximum additional timeinformation box 230 are the same as the embodiment shown in FIG. 1.

The time input box 220 is preferably provided to the user in anactivated state like the embodiment shown in FIG. 1, and the user caninput the amount of time to be additionally secured through the timeinput box 220. The time input box 220 can selectively include a text box121 or a slider 223 or both of them. Also, the user interface mayinclude one or more check boxes 226, 227, and 228. The embodiment shownin FIG. 2 may further include a reliability indication box 229 inaddition to the embodiment shown in FIG. 1. The user can select adesired additional time by clicking and dragging a slider bar 222 on theslider 223 with an input device. Actually, the selected additional timecannot always be secured. This is because the CPU resource consumed byapplications and the amount of power consumed by peripheral devices mayvary. Thus, in this embodiment, the relationship between reliability andan additional time, which is statistically obtained throughexperimentation by the manufacturer, is further included for a user'sreference when the user selects a desired additional time. For example,when the maximum additional time is 62 minutes, if the user selects 62minutes as an additional time, the reliability indication box 229 mayindicate that 62 minutes is secured with a reliability of 75%. In otherwords, in selecting 62 minutes as the additional time, the user can takeinto consideration a 25% chance that the additional time selected by theuser may not be secured. In other words, according to this embodiment,the user can select a proper additional time based on the reliability ofthe battery power supply.

In this embodiment, the after-input battery information box 240 mayfurther provide reliability information in addition to information aboutthe remaining battery capacity and the remaining battery time after theuser inputs the additional time. In other words, the user can determinea current remaining battery time through the after-input batteryinformation box 240 after inputting an additional time and understandthat there is a 91% probability that the power supply will securelyprovide power for the current remaining battery time.

Like the embodiment shown in FIG. 1, the user interface may include anOK button 250, a cancel button 251, and an apply button 252.

Although the user inputs a desired additional time in the embodimentsshown in FIGS. 1 and 2, the user may input the amount of time the useractually desires to use. In this case, the maximum additional timeinformation box 230 is changed to a maximum available time informationbox and the time input box 220 may selectively include a text box intowhich the user can input a total user time (current remaining batterytime+additional time) and/or a slider.

FIG. 3 is a flowchart illustrating a process for managing the power of aportable computer system according to an embodiment of the presentinvention.

In step S310, the power level of a computer system is set to the minimumpower level. In other words, the power level of the computer system ismeasured in a state where preferably the operating speed of a CPU is setto the minimum value and an HDD or ODD is powered off.

Once the power level of the computer system is set to the minimum powerlevel, a maximum additional time is calculated based on the powerconsumption at the minimum power level and a current remaining batterycapacity in step S320. The maximum additional time can be obtained bysubtracting a current remaining battery time at a current power levelfrom a current remaining battery time at the minimum power level. Theobtained maximum additional time is provided to a user via a userinterface, such as the graphical user interfaces shown in FIGS. 1 and 2,respectively.

The user then inputs an additional time (S330). Upon a user's input ofthe additional time, the power level is reset (S340). The user cansecure the input additional time by resetting the power level lower thanthe current power level. Resetting of the power level will be describedin more detail with reference to FIG. 4.

After the power level is reset, the user uses a computer for the desiredamount of time in step S350.

FIG. 4 is a flowchart illustrating in detail a process for resetting apower level according to an embodiment of the present invention.

First, in step S410, the remaining battery time is calculated at acurrent power level. It is determined in step S420 whether the remainingbattery time exceeds a total user time. The total user time means afinal time to be secured after the user's input of the additional time.For example, when the remaining battery time is 1 hour and theadditional time input by the user is 30 minutes, the total user time is1 hour and 30 minutes.

When the remaining battery time does not exceed the total user time, itis determined in step S430 whether a device is at the minimum powerlevel. If the device is not at the minimum power level, a power mode ofthe device is reset lower than a current power mode in step S440.Resetting of the power mode of the device will be described in moredetail with reference to FIG. 5. After the power mode of the device isreset, the remaining battery time is calculated again in step S410. Itis determined again in step S420 whether the remaining battery timeexceeds the total user time. If the remaining battery time calculatedwhile gradually reducing the power level of each device through theforegoing process exceeds the total user time, the power mode of eachdevice is set to a power mode corresponding to the power level of eachdevice in step S450. If a device reaches the minimum power level in astate where the remaining battery time does not exceed the total usertime, the maximum available time in such a state is calculated again instep S460. The user is then informed of the fact that a portablecomputer system cannot operate up to the total user time and of theupdated maximum available time in step S470. The user may input a newadditional time based on the updated maximum available time.

In the embodiment shown in FIG. 4, the power level of the portablecomputer system is reset while gradually reducing the power level ofeach device until the remaining battery time exceeds the total usertime. However, such a reduction is only an example, and the power levelof the portable computer system may be reset while gradually reducingthe power level of each device after setting an initial power level ofeach device based on the remaining battery time and the total user time.For example, if the remaining battery time is 1 hour and the total usertime is 1 hour and 30 minutes, steps S410 through S470 may be performedto set the final power level of each device of the portable computersystem after the initial power level of each device of the portablecomputer system is pre-set such that the power consumption of theportable computer system becomes about ⅔ of the current powerconsumption.

FIG. 5 is a flowchart illustrating in detail a process for resetting apower mode of a device according to an embodiment of the presentinvention.

In step S510, it is determined whether a device of importance, such as aCCD, HDD or ODD, is set through a check box. If a device of importanceis set, it is determined in step S520 whether a device of non-importanceis in a minimum power mode. If the device of non-importance is not inthe minimum power mode, the power level of the device of non-importanceis reduced to the minimum power level in step S530.

If the device of non-importance is in the minimum power mode, it isdetermined in step S540 whether the power mode of the device ofimportance exceeds a reference power mode. The reference power modeindicates a lower limit of the power level to which the power level ofthe device of importance can be reduced. For example, when an LCD is thedevice of importance and the power level of the LCD is preset to bemaintained higher than 50%, a power mode where the power level of theLCD is 50% is the reference power mode. However, if the LCD is not thedevice of importance, the reference power mode may be a power mode wherethe power level of the LCD is 0%. If the power mode of the device ofimportance exceeds the reference power mode, the power level of thedevice of importance is reduced in step S550. If the power mode of thedevice of importance is below the reference power mode, the power levelof the device of importance is not reduced.

If the device of importance is not set, it is determined in step S560whether all the devices of the portable computer system are in theminimum power mode. If all the devices are not in the minimum powermode, the power level of a device that is not in the minimum power modeis reduced in step S570. If all the devices are in the minimum powermode, the power level is not reduced for any of the devices.

FIG. 6 is a flowchart illustrating a process for managing the power of aportable computer system according to another embodiment of the presentinvention.

In step S610, the power level of the portable computer system is set tothe minimum power level. In other words, the power level of the portablecomputer system is measured in a state where the operating speed of theCPU is set to the minimum value and an HDD or ODD is powered off.

Once the power level of the portable computer system is set to theminimum power level, the maximum additional time is calculated based onpower consumption at that time and the remaining battery capacity instep S620. The maximum additional time can be obtained by subtractingthe remaining battery time at a current power level from the remainingbattery time at the minimum power level. The obtained maximum additionaltime is provided to a user.

The user then inputs an additional time in step S630. Upon the user'sinput of the additional time, the power level of the portable computersystem is reset in step S640. The additional time input by the user canbe obtained by resetting the power level lower than the current powerlevel. Resetting of the power level is already described with referenceto FIG. 4.

After the power level is reset, the user uses a computer for a desiredamount of time in step S650. A remaining battery time is periodicallymeasured at predetermined time intervals, such as in 10 minuteintervals, (S660) during the use of the computer. After the remainingbattery time is measured, it is determined in step S670 whether thebattery in its current state can still obtain the total user time. Sucha process is required because the total user time may not be securedwith the remaining battery time obtained by reducing the power levelthrough a power level resetting process (step S640). For example, whenthe amount of power used by the CPU of the portable computer systemsharply increases, the amount of power consumption increases. In thiscase, the embodiment of FIG. 3 may not secure the total user time.However, the embodiment shown in FIG. 6 can obtain the total user timeby further including the step of determining whether the total user timecan be secured.

In other words, if it is determined that the total user time cannot besecured, the power level of each device is reset through the power levelresetting process (step S640). The user then uses the computer in stepS650. The power level resetting process (step S640) may be automaticallyperformed without the user's specific manipulation as described above.

FIG. 7 is a block diagram of an apparatus for managing the power of aportable computer system according to an embodiment of the presentinvention.

An apparatus 710 for managing the power of a portable computer systemcomprises a graphical user interface 712, a power manager 714, and acalculation agent 716.

The graphical user interface 712 provides a user with information suchas a current battery state and the maximum available time of theportable computer system and a time input box into which a user caninput an additional time.

The power manager 714 resets the power level of the portable computersystem while reducing the power level of each device of the portablecomputer system so that the remaining battery time can be greater than atotal user time including an additional time input through the graphicaluser interface 712.

The calculation agent 716 calculates the maximum additional time bysubtracting a current remaining battery time at a current power levelfrom a current remaining battery time at the minimum power level.

A battery unit 720 of the portable computer system comprises a battery722 that converts chemical energy into electrical energy and a batterycontrol unit 724 that checks the state of a battery and calculates theremaining capacity of the battery and the remaining amount of time thatthe battery will be capable of supplying sufficient power. The remainingbattery capacity and time information of the battery unit 720 aretransferred to the power manager 714.

The power manager 714 controls the power levels of the various devicesincluded in the portable computer system. Examples of the devicesincluded in the portable computer system are a speaker 732, an ODD 734,an HDD 736, an LCD 738, and a CPU 739. Each of the devices preferablyincludes its own controller. For example, the controllers may be aspeaker controller 731 that controls the volume and tone of the speaker732, an ODD controller 733 controls the reading, writing and deletingoperations of the ODD 734, an HDD controller 735 that controls reading,writing and eliminating operations of the HDD 736, and an LCD controller737 that controls the brightness or color of the LCD 738.

According to the embodiments of the present invention, a user can obtaina desired time to use a portable computer system by merely inputtingdesired time information without having to input complicated settinginformation. To this end, the embodiments of the present inventionprovide a range of desired time that can be input by the user and a timeinput box into which the user can input the desired time. Thus, thepower level of a device that is regarded by a user as more importantthan other devices is reduced last after the power levels of the otherdevices are reduced. Thus, the user can use a portable computer for adesired amount of time in an optimized environment.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A method for managing the power of a portable computer system, themethod comprising the steps of: calculating a range of a desiredtime-of-use based on power consumption at a minimum power level and aremaining battery capacity of the portable computer system; providingthe calculated range of the desired time-of-use and a desired time inputbox on a user interface that allows a user to input the desiredtime-of-use; inputting the desired time-of-use through the desired timeinput box; and resetting the power level of the portable computer systemaccording to the input desired time-of-use.
 2. The method of claim 1,wherein the desired time input box comprises a text box that allows theuser to input the desired time-of-use in the form of a number.
 3. Themethod of claim 1, wherein the desired time input box comprises a sliderhaving a continuous time value and a slider bar that moves on the sliderand allows the user to determine the desired time-of-use according touser's selection.
 4. The method of claim 1, wherein calculating therange of the desired time-of-use comprises the steps of: calculating aminimum power consumption of the portable computer system by setting thepower level of each device included in the portable computer system to aminimum power level; and calculating the range of the desiredtime-of-use using the minimum power consumption and a remaining batterycapacity.
 5. The method of claim 1, wherein the step of resetting of thepower level further comprises the step of gradually reducing the powerlevel of each device included in the portable computer system until thedesired time-of-use exceeds a remaining battery time.
 6. The method ofclaim 1, further comprising the step of providing a check box forselecting the importance of one or more devices included in the portablecomputer system.
 7. The method of claim 6, wherein the step of resettingof the power level further comprises the step of gradually reducing thepower level of the device that is not checked in the check box.
 8. Themethod of claim 1, wherein the resetting of the power level furthercomprises the steps of: setting an initial power level of each deviceaccording to the desired time-of-use and the remaining battery time; andsetting a final power level of each device included in the portablecomputer system by reducing the power level of each device until thedesired time-of-use exceeds the remaining battery time.
 9. The method ofclaim 1, further comprising the step of determining whether a total usertime is obtained after resetting of the power level, wherein if thetotal user time is not obtained, the power level is reset.
 10. Anapparatus for managing the power of a portable computer system, theapparatus comprising: a graphical user interface which provides a userwith a range of a desired time-of-use that is calculated based on powerconsumption at a minimum power level and a remaining battery capacity ofthe portable computer system and comprises a desired time input box thatallows the user to input the desired time-of-use as selected by theuser; and a power manager which resets the power level of the portablecomputer system such that a total user time including the desiredtime-of-use input through the graphical user interface exceeds theremaining battery time.
 11. The apparatus of claim 10, wherein thedesired time input box comprises a text box that allows the user toinput the desired time-of-use in the form of a number.
 12. The apparatusof claim 10, wherein the desired time input box includes a slider havinga continuous time value and a slider bar that moves on the slider andallows the user to determine the desired time-of-use according to user'sselection.
 13. The apparatus of claim 10, wherein the graphical userinterface further comprises a check box for selecting the importance ofone or more devices included in the portable computer system, whereinthe power manager gradually reduces the power level of the device thatis not checked in the check box.
 14. The apparatus of claim 10, whereinthe power manager sets an initial power level of each device accordingto the desired time-of-use and the remaining battery time and sets afinal power level of each device by reducing the power level of eachdevice until the desired time-of-use exceeds the remaining battery time.15. The apparatus of claim 10, wherein the power manger determineswhether a total user time is secured after resetting of the power leveland resets the power level if the total user time is not secured.
 16. Aportable computer system comprising: a battery unit which suppliespower; a plurality of devices which provide predetermined functions; agraphical user interface which provides a user with a range of a desiredtime-of-use that is calculated based on power consumption at a minimumpower level and a remaining battery capacity of the portable computersystem and includes a desired time input box that allows the user toinput the desired time-of-use as selected by the user; and a powermanager which resets the power level of the portable computer systemsuch that a total user time including the desired time-of-use inputthrough the graphical user interface exceeds the remaining battery time.17. The portable computer system of claim 16, wherein the desired timeinput box comprises a text box that allows the user to input thedesired-of-use time in the form of a number.
 18. The portable computersystem of claim 16, wherein the desired time input box comprises aslider having a continuous time value and a slider bar that moves on theslider and allows the user to determine the desired time-of-useaccording to a user's selection.
 19. The portable computer system ofclaim 16, wherein the graphical user interface further comprises a checkbox for selecting the importance of one or more devices included in theportable computer system and the power manager gradually reduces thepower level of the device that is not checked in the check box.
 20. Theportable computer system of claim 16, wherein the power manager sets aninitial power level of each device according to the desired time-of-useand the remaining battery time and sets a final power level of eachdevice included in the portable computer system by reducing the powerlevel of each device until the desired time-of-use exceeds the remainingbattery time.
 21. The portable computer system of claim 16, wherein thepower manger determines whether a total user time is secured afterresetting of the power level and resets the power level if the totaluser time is not secured.
 22. A recording medium having a computerreadable program recorded therein, the program for executing a methodfor managing the power of a portable computer system, the methodcomprising: calculating a range of a desired time-of-use based on powerconsumption at a minimum power level and a remaining battery capacity ofthe portable computer system; providing the calculated range of thedesired time-of-use and a desired time input box on a user interf